1. Field of the Invention
The present invention relates to dimple arrangement of a golf ball which allows to extend its flying distance, and more particularly to such dimple arrangement which allows to reduce the drag coefficient of the golf ball and minimize the air resistance by making the continuous regions of air stream and, in particular by arranging the large dimple in those regions to flow out the collided air easily in a low-speed area during its flying.
2. Description of the Relevant Art
Generally, in the case of the circular shape or elliptical shape of dimples of a golf ball, the dimples are arranged by dividing the outer surface of a golf ball into the faces of a spherical polyhedron in which the kinds of the faces are composed of polygons such as triangle, square, pentagon, hexagon, heptagon, octagon and so on. And, the dimples are arranged by using one of those kinds or two kinds, or three kinds, in the divisional surface of the sphere. But, restrictions will happen by the dimples being arranged in an identical polygon which coincide with the symmetrical polygon in order to achieve a spherical symmetry of the golf ball by the rule of RandA and U.S.G.A. That is, the dimples being arranged one kind of identical size and shape or some kinds of size in a polygon of the aforementioned polyhedron, the dimples cannot help being arranged evenly in size and shape in the case of many kinds of dimples. Even if the polygon which holds a vertex in common, or holds a side in common, or apart from another, is accomplished a symmetry between identical polygons which are composed of a, spherical polyhedron, the dimples are distributed intermittently in each polygon, therefore there is no dividing method which guiding out the air-flow by the continuous connection of the groups of larger sized dimples that allows to reduce the drag coefficient of the golf ball in a low-speed area during its flying. As a golfer hits a golf ball, strong repulsive elasticity is generated on the ball by the power applied from the head of a golf club, and the back-spin is generated by the loft angle of a golf club. The impacted ball as explained above will fly at high speed, obtained the aid of aerodynamic lift, the golf ball flies at high speed until the apex of trajectory and at low-speed till the landing point from the apex of trajectory. In the case of circular dimples, the dimple coverage for obtaining the sufficient aerodynamic lift in a high-speed area should be more than 76% about all of the surface of golf ball, and it is possible for a desired carry distance to obtain aerodynamic lift when the number of dimples whose size is more than 0.145xe2x80x3 (3.683 mm) shared more than 60% among the total number of dimples in the surface of golf ball. Even though the dimple coverage is more than 76% when the number of dimples whose size is more than 0.145xe2x80x3 (3.683 mm) shared less than 60% among the total number of dimples, it is difficult to obtain sufficient aerodynamic lift in a high-speed area and increase the carry distance by a severe pressure drag in a low-speed area. There is no doubt that it should be helpful to obtain the aerodynamic lift by deepening the depth of the dimples whose size is less than 0.145xe2x80x3 (hereinafter referred as small dimples), but when the depth of dimples which have a diameter from 0.115xe2x80x3 to 0.145xe2x80x3 is more than 6% about the diameter, the carry distance decrease by increasing the pressure drag abruptly that caused a so-called Hop due to making the whirlpool excessively in the air stream in a high-speed area. On the other hand, in the case of dimples which have the diameter more than 0.145xe2x80x3 (hereinafter referred as large dimples), the proper depth is 0.006xe2x80x3xcx9c0.0075xe2x80x3 by reason that the carry distance is able to decrease since, in a high-speed area, the pressure drag applied in the large dimples is enlarged remarkably compared to the small dimples. In the case of small dimples whose depth is 0.0057xe2x80x3xcx9c0.0062xe2x80x3, although an influence upon the aerodynamic lift in a high speed area is immaterial compared to the large dimples, the small dimples act as a controller against the excessive higher trajectory by decreasing the higher pressure drag of large dimples in a high-speed area, and act as a flying stabilizer by preventing the golf ball from fluttering by the hard wind, of which the air-flow is distributed into smaller size over the surface of the golf ball in a low-speed area. But, the pressure drag is increased in a low-speed area by the small dimples basically compared to the large dimples, so it is important to arrange the large dimples and small dimples properly in a dimple arrangement. Accordingly, acting to the best of the ability of large dimples in a low-speed area is the most important factor of carry distance in the dimple arrangement.
Therefore, it is an object of the present invention to provide a new divisional composition in the surface of sphere different from a common divisional composition to increase the carry distance of the golf ball.
It is another object of the present invention to provide dimple arrangement of a golf ball which allows to reduce the drag coefficient of the golf ball and minimize the air resistance by making the continuous regions of air stream and arranging the large dimples in those regions to flow out the collided air easily in a low-speed area during its flying.
The present invention provides a new divisional composition in the surface of sphere different from a common divisional composition, in which a golf ball has a plurality of dimples in its spherical outer surface and its spherical outer surface is divided by a great circle path which passing through the points P1(longitude0 degree, latitude0 degree), P2(longitude30 degree, latitude54.7356098 degree), P13(longitude150 degree, latitude54.7356098 degree) and P14(longitude180 degree, latitude0 degree), while an arbitrary point of its spherical outer surface acts as a pole, and further divided by a great circle path which passing through the points P6(longitude60 degree, latitude0 degree), P2, P18(longitude270 degree, latitude54.7356098 degree) and P20(longitude 240 degree, latitude0 degree), further divided by a great circle path which passing through the points P10(longitude120 degree, latitude0 degree), P13, P18 and P23(longitude300 degree, latitude0 degree), further divided by a great circle path which passing through the points P1, P5(longitude60 degree, latitude 35.26438969 degree) and P14, further divided by a great circle path which passing through the points P7(longitude 79.1066054 degree, latitude0 degree), P25(longitude 330 degree, latitude54.7356098 degree) and P21(longitude 259.1066054 degree, latitude0 degree), further divided by a great circle path which passing through the points P9(longitude 100.89339465 degree, latitude 0 degree), P17(longitude210 degree, latitude54.7356098 degree) and P22(longitude 280.89339465 degree, latitude0 degree), further divided by a great circle path which passing through the points P10, P15(longitude180 degree, latitude 35.26438969 degree) and P23, further divided by a great circle path which passing through the points P16(longitude 199.1066054 degree, latitude 0 degree), P8(longitude 90 degree, latitude 54.7356098 degree) and P3(longitude 19.1066054 degree, latitude 0 degree), further divided by a great circle path which passing through the points P19(longitude 220.89339465 degree, latitude 0 degree), P25 and P4(longitude 40.89339465 degree, latitude 0 degree), further divided by a great circle path which passing through the points P20, P27(longitude 0 degree, latitude 35.26438969) and P6, further divided by a great circle path which passing through the points P24(longitude 319.1066054 degree, latitude 0 degree), P17 and P11(longitude 139.1066054 degree, latitude 0 degree), further divided by a great circle path which passing through the points P26(longitude 340.89339465 degree, latitude 0 degree), P8 and P12(longitude 160.89339465 degree, latitude 0 degree), and the spherical outer surface is further divided by a great circle path which acts as a equator, passing through the points P1, P7, P14, P16, and P24.
Regarding the dimple arrangement, the dimples in the regions(F1, F2, F3, F4, F5, F6, F7, F8, F9) which are able to induce the continuous regions of air stream in the surface of golf ball, in particular, indicated by the black slanting lines in FIG. 4 are relatively larger than those of the large spherical triangle in the central region in the surface of the sphere by above 10% in size, and connected to the first large size dimples which exist one by one in the regions of S1, S2, S3 (6 regions exist included same regions in the opposite side of the sphere.) respectively in the surface of the golf ball in a form of band. Accordingly, the drag coefficient of the golf ball is reduced and the air resistance is minimized by making the continuous regions of air stream and arranging the large dimples in those regions to flow out the collided air easily in a low-speed area during its flying, and therefore the carry distance is increased.